/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.format.datetime.joda;

import java.util.Calendar;
import java.util.Collections;
import java.util.Date;
import java.util.HashSet;
import java.util.Set;

import org.joda.time.LocalDate;
import org.joda.time.LocalDateTime;
import org.joda.time.LocalTime;
import org.joda.time.ReadableInstant;
import org.joda.time.ReadablePartial;
import org.joda.time.format.DateTimeFormatter;

import org.springframework.context.support.EmbeddedValueResolutionSupport;
import org.springframework.format.AnnotationFormatterFactory;
import org.springframework.format.Parser;
import org.springframework.format.Printer;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.util.StringUtils;

/**
 * Formats fields annotated with the {@link DateTimeFormat} annotation using Joda-Time.
 *
 * <p><b>NOTE:</b> Spring's Joda-Time support requires Joda-Time 2.x, as of Spring 4.0.
 *
 * @author Keith Donald
 * @author Juergen Hoeller
 * @see DateTimeFormat
 * @since 3.0
 */
public class JodaDateTimeFormatAnnotationFormatterFactory extends EmbeddedValueResolutionSupport
        implements AnnotationFormatterFactory<DateTimeFormat> {

    private static final Set<Class<?>> FIELD_TYPES;

    static {
        // Create the set of field types that may be annotated with @DateTimeFormat.
        // Note: the 3 ReadablePartial concrete types are registered explicitly since
        // addFormatterForFieldType rules exist for each of these types
        // (if we did not do this, the default byType rules for LocalDate, LocalTime,
        // and LocalDateTime would take precedence over the annotation rule, which
        // is not what we want)
        Set<Class<?>> fieldTypes = new HashSet<>(8);
        fieldTypes.add(ReadableInstant.class);
        fieldTypes.add(LocalDate.class);
        fieldTypes.add(LocalTime.class);
        fieldTypes.add(LocalDateTime.class);
        fieldTypes.add(Date.class);
        fieldTypes.add(Calendar.class);
        fieldTypes.add(Long.class);
        FIELD_TYPES = Collections.unmodifiableSet(fieldTypes);
    }


    @Override
    public final Set<Class<?>> getFieldTypes() {
        return FIELD_TYPES;
    }

    @Override
    public Printer<?> getPrinter(DateTimeFormat annotation, Class<?> fieldType) {
        DateTimeFormatter formatter = getFormatter(annotation, fieldType);
        if (ReadablePartial.class.isAssignableFrom(fieldType)) {
            return new ReadablePartialPrinter(formatter);
        } else if (ReadableInstant.class.isAssignableFrom(fieldType) || Calendar.class.isAssignableFrom(fieldType)) {
            // assumes Calendar->ReadableInstant converter is registered
            return new ReadableInstantPrinter(formatter);
        } else {
            // assumes Date->Long converter is registered
            return new MillisecondInstantPrinter(formatter);
        }
    }

    @Override
    public Parser<?> getParser(DateTimeFormat annotation, Class<?> fieldType) {
        if (LocalDate.class == fieldType) {
            return new LocalDateParser(getFormatter(annotation, fieldType));
        } else if (LocalTime.class == fieldType) {
            return new LocalTimeParser(getFormatter(annotation, fieldType));
        } else if (LocalDateTime.class == fieldType) {
            return new LocalDateTimeParser(getFormatter(annotation, fieldType));
        } else {
            return new DateTimeParser(getFormatter(annotation, fieldType));
        }
    }

    /**
     * Factory method used to create a {@link DateTimeFormatter}.
     *
     * @param annotation the format annotation for the field
     * @param fieldType  the type of field
     * @return a {@link DateTimeFormatter} instance
     * @since 3.2
     */
    protected DateTimeFormatter getFormatter(DateTimeFormat annotation, Class<?> fieldType) {
        DateTimeFormatterFactory factory = new DateTimeFormatterFactory();
        String style = resolveEmbeddedValue(annotation.style());
        if (StringUtils.hasLength(style)) {
            factory.setStyle(style);
        }
        factory.setIso(annotation.iso());
        String pattern = resolveEmbeddedValue(annotation.pattern());
        if (StringUtils.hasLength(pattern)) {
            factory.setPattern(pattern);
        }
        return factory.createDateTimeFormatter();
    }

}
